You may find that you have more routes already on your computer that you can't see in the list. Turn off the gold star for "favourites" at the top of the routes menu (click on it).
Recently made content when downloaded should automatically appear in the menu. If it doesn't it's probably because it is incomplete and needs further "dependancies" to operate that may need to be found seperately. If you right mouse click while highlighting a route in Content Manager you can find out what dependancies are missing. Beware that there may be items not on Auran's download station, which can't be found by the Trainz automatic searches. These have to be found on users private websites, which can be difficult to find.
Look through posting on the forum for "Freeware Announcements" for links to stuff not on Auran's servers.
You could always try reading the manual, which will tell you how to use the program and download system........